I love mine too. I have been told that they can be a little finicky about mags. If you have trouble with feeding from those mags, try Brownell's (which may be the blackdog, I don't know). I haven't had any problems with mine. It's great to go out & just shoot the heck out of it for $5.
I received my Spikes Tactical .22 conversion kit the other day and brought it out to the range for the first time today. It came with 1 BlackDog 27 round magazine and I bought 2 more to go with it. I had a few random FTE's, but as a whole it ran great. Sooting 500 rounds out of my AR while spending less than $15 in ammo is a great feeling, and based off of that the kit already paid for itself today. I really need to get a nice .22 pistol to add to the collection now.